DESCRIPTION A clinical study following 357 breast cancer patients has been completed in Chile. Several factors were analyzed, including the stage of tumor at diagnosis, survival rate stratified by stage of tumor at diagnosis, type of metastasis, and other factors describing the effect of treatment for breast cancer among women in Chile. In 1990, a breast-ovarian cancer susceptibility gene (BRCA1) was found to be linked to chromosome 17q21 and was subsequently cloned (Hall et al 1990, Miki et al 1994). We propose to screen for germline BRCA1 mutations in chilean families at high risk for breast and ovarian cancer. We will transfer genetic screening technology to our Chilean colleagues in a manner that is cost effective and sustainable. Initially we will contact the probands from the original study and obtain pedigrees. Pedigrees which have characteristics of founder mutations unique to the Chilean population. We will be enabling Chile and other countries in Latin America to identify germline BRCA1 mutations and contribute their results to the global scientific community. This will be a significant contribution, since the prevalence and effects of mutations in a given population will allow genetic testing to be more effective and mower women to make educated decisions on preventative treatment and reproduction choices.